add reset_db method

aiida/backends/utils.py

@@ -283,5 +283,3 @@ def _get_column(colname, alias):
                     '\n'.join(alias._sa_class_manager.mapper.c.keys())
                 )
         )
-
-

aiida/utils/fixtures.py

@@ -35,6 +35,13 @@ class FixtureManager(object):
 
         # ready for testing
 
+        # run test 1
+
+        fixtures.reset_db()
+        # database ready for independent test 2
+
+        # run test 2
+
         fixtures.destroy_all()
         # everything cleaned up
     """
@@ -109,6 +116,16 @@ def create_profile(self):
         aiida_cfg.set_default_profile('daemon', profile_name)
         self.__is_running_on_test_profile = True
 
+    def reset_db(self):
+        """Cleans all data from the database between tests"""
+        if not self.__is_running_on_test_profile:
+            raise FixtureError(
+                'No test profile has been set up yet, can not reset the db')
+        if self.profile_info['backend'] == 'django':
+            self.__clean_db_django()
+        elif self.profile_info['backend'] == 'sqla':
+            self.__clean_db_sqla()
+
     @property
     def profile(self):
         """Profile parameters"""
@@ -257,6 +274,16 @@ def destroy_all(self):
         if self.pg_cluster:
             self.pg_cluster.close()
 
+    @staticmethod
+    def __clean_db_django():
+        from aiida.backends.djsite.db.testbase import DjangoTests
+        DjangoTests().clean_db()
+
+    @staticmethod
+    def __clean_db_sqla():
+        from aiida.backends.sqlalchemy.tests.testbase import SqlAlchemyTests
+        SqlAlchemyTests().clean_db()
+
 
 @contextmanager
 def plugin_fixture():